Math Is Fun Forum

Identity

Member

Registered: 2007-04-18

Posts: 934

Standard Deviation

Let

and

denote the sample mean and variance for the sample

, and le

and

denote these quantities when an additional observation,

is added to the sample.

Show that
a) Show how

can be computed from

and

.

b) Show that

I've done question a) but I'm stuck on question b) can anyone please help!

Last edited by Identity (2009-09-10 21:05:25)

rzaidan

Member

Registered: 2009-08-13

Posts: 59

Re: Standard Deviation

Hi Identity ,
If you can -please- tell me first how I can  write the notations of the mean ,the standard deviation,....since it is difficult to write these notations directly and the answer I think is easy!!!!!!!!!!!!
Thanks
Riad Zaidan

Identity

Member

Registered: 2007-04-18

Posts: 934

Re: Standard Deviation

You can click on the symbols to find out how to write them in latex

is   \bar{x}_n

is s_n^2

is \frac{n}{n-1}

thankyou

rzaidan

Member

Registered: 2009-08-13

Posts: 59

Re: Standard Deviation

Dear Identity
How can I download latex?
Thanks

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Standard Deviation

Hi rzaidan;

Check this site out: It is a online latex editor.

http://latex.codecogs.com/editor.php

Last edited by bobbym (2009-09-12 10:08:59)

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Identity

Member

Registered: 2007-04-18

Posts: 934

Re: Standard Deviation

The forum already has it installed if you want to use it, just put

tags around the latex

Last edited by Identity (2009-09-12 22:36:54)